1. Field of the Invention
The present invention relates to an integrated control system (apparatus) for a work robot that is capable of processing robot control and work tool control at a high speed.
2. Description of Related Art
Japanese Patent Publication No. HEI 7-144283 discloses a control system wherein a robot control system and a work tool (servo welding gun) control system are linked by a communication channel (telephone line). More particularly, in the control system, the robot control CPU (central processing unit) and the servo gun control CPU are constructed independently of each other and are connected by the communication channel, causing the robot and servo gun control units to have a large space therebetween and operate independently of each other.
However, the above-described system has the following problems:
(1) It takes a relatively long communication time period to link the CPUs. It is impossible to conduct parallel calculations because of its limited calculation ability. As a result, control of peripheral equipment is delayed, which lowers the control characteristic of the control system.
(2) Since it is impossible to conduct real time, simultaneous control of both the pressing force and welding electrical current during welding, a high grade of weld cannot be yielded.
(3) A hardware such as a communication channel between the units and a software such as a control logic must be prepared to accommodate the independent circuits even though it greatly complicates the circuitry overall.
(4) Despite these problems, there is common information, such as pressing force information, locus information, and input/output information from and to the peripheral equipment in the work control and the robot control, and yet this information has not been previously used together in one common circuit. In addition, the control unit was constructed such that the information about the welding electrical current, the expansion amount of the plates to be welded, and the electrical resistance between the electrodes could not be fed back from the work control to the robot control.